1. Field of the Invention
The invention relates to a split cage and a roller bearing.
2. Description of the Related Art
As a cage that holds a plurality of rollers, which roll between an inner ring and an outer ring of a roller bearing, at prescribed intervals along the circumferential direction of the cage, there is a conventional split cage formed of a plurality of cage segments arranged in a circular pattern along the circumferential direction and each having a single pocket that accommodates a single roller (refer to, for example, Japanese Patent Application Publication No. 2011-133061). As this type of split cage, there is often adopted a cage of a roller guidance type, of which the turning is guided by rollers in order to prevent abrasion of the cage due to contact with inner and outer rings.
In the split cage of the roller guidance type, turning of each cage segment is guided by the roller, and thus a prescribed radial clearance is formed between each of the cage segments and the inner peripheral face of the outer ring in normal times. Thus, if a clearance between adjacent cage segments in the circumferential direction is eliminated due to thermal expansion of the cage segments, each cage segment may be displaced radially outward (toward the inner peripheral face of the outer ring) because an allowance for the cage segment in the circumferential direction is lost. In this case, each of the cage segments is displaced radially outward in a state where a radially inner portion of a pocket-side face, with which the roller is in sliding contact, is strongly pushed against the roller due to the thermal expansion. As a result, abnormal abrasion between the radially inner portion and the roller is likely to occur.